I have not been there myself, but have heard from some friends with pre-teen to teen daughters that
Spa Jane is very girly...
Avalon inside North Star (right inside the entrance by Security Credit Union) is decent - better than a typical mall nail place, but a little more expensive than them as well ($28 for basic pedi, $35 for one with foot mask and hot towel).
There's also
Aveda Institute. I've only had one pedicure there and I didn't love it because they don't use water, but maybe you have to get used to it. Prices are reasonable and I do love the facials there...